Because the LCD has the features of low radiation, small size and low power consumption, the conventional cathode ray tube (CRT) display is gradually replaced by LCD panel which is widely used in a variety of products including notebook computer, personal digital assistant (PDA), flat television and mobile phone etc.
FIG. 1 is a schematic relationship view between scan signal and data signal when performing a conventional LCD driving method. The action principle of LCD is that the data signal is recorded (written) into the liquid crystal molecules based on the scan signal 100 of the gate electrode to generate the display signals. Conventionally, the scan signal is transmitted from top to bottom in the display frame of LCD panel wherein the waveform height (Vgh) and the waveform width (GPW) maintain the same level during the transmission. That is, the same waveform height (Vgh) represents that the waveform height (Vgh) has the constant duty duration of voltage level and the waveform width (GPW) has the constant time period.
The color filter layer having red, green and blue colors is disposed in each pixel unit and the pixel regions corresponding to the red, green and blue colors are termed as sub-pixel. When performing color tracking, i.e. color temperature detection, on the LCD in the prior art, the white color tends to blue if color temperature is higher and the white color tends to yellow if color temperature is lower. The reason is that three primary colors, i.e. red (R), green (G) and blue (B) colors are inconsistent. That is, the RGB primary color cannot form a predetermined color ratio based on the data signal so that voltage-transmittance curves of RGB primary color are different. Such the situation results in color ratio deviation of RGB primary color in different gray levels, i.e. color shifting, when the same gray level is applied to the LCD panel. A manufacturing procedure is used to solve the above problem. The RGB colors have different liquid crystal height to change the voltage and transmittance thereof for compensating the voltage-transmittance curve. However, the manufacturing procedure easily deviates due to operation conditions, which cannot improve the color shifting.
Additionally, since the material characteristic of color-resisting layer of color filter in the COA is varied, different dielectric constant of three primary color RGB, the capacitance (Cgs) between the gate electrode and pixel electrode is different so that the feed-through voltages of RGB change and thus the response time of the three primary color RGB varies, i.e. the color shifting, in the same gray level.
Consequently, there is a need to develop a driving method of LCD to solve the aforementioned problem of the color temperature deviation and response time inconsistence of the three primary color RGB.